Another “world’s …est” postcard, this time described in the caption as “the World’s Largest Suspension Bridge”.  This is a designation Google refuses to recognize, though the honour now might go to the Akashi Kaikyō Bridge in Kobe (Japan), with Mackinac well down the list.  In any case, of course it’s impressive — more than the postcard itself, which is unused but has significant smudging on the reverse.  Grade: 3